1. Field of the Invention
The present invention relates to a hot-melt type ink-jet printer for heating and melting solid hot-melt ink at ordinary temperatures and ejecting the melted ink through a nozzle as liquid ink to thereby print and record characters or the like.
2. Description of the Related Art
An ink-jet printer having a hot-melt type ink-jet head has heretofore been known wherein solid ink is held within an ink tank and is heated and melted so as to be ejected through a nozzle as liquid ink, thereby printing characters. This type of ink-jet printer starts printing after the temperature of each ink passage of the ink-jet head and the temperature of the ink held in the ink tank has reached an intended ink temperature determined according to the type of ink. The term "intended ink temperature" means such a temperature as the viscosity of the ink becomes a value (generally 3 to 50 cPs, preferably 5 to 20 cPs) suited to discharge the ink as droplets.
However, since the ink is exposed to air in the vicinity of the nozzle, although the ink is heated to a sufficiently high temperature within the ink-jet head including the ink tank, the temperature of the ink is lowered and hence becomes apt to be solidified. Therefore, a heating means having a nozzle hole defined in a thermal-conductive plate-like member and provided in the vicinity of the nozzle hole defined in the surface of the plate-like member has been disclosed in Japanese Unexamined Patent Publication No. 3-253344 in order to efficiently prevent the temperature of the ink exposed to air in the vicinity of the nozzle from decreasing.
It is, however, difficult in practice to provide the heating means in the vicinity of the nozzle hole defined in the surface of the plate-like member. Further, the heating means becomes complex in structure. Since only the neighborhood of the nozzle hole is heated, the effect of heating the whole area lying in the vicinity of the nozzle cannot be sufficiently achieved.